THE PRESIDENTIAL ADDRESS 2005

Maurice Moss delivered his final Presidential Address on the 17th May.

A good turnout awaits Maurice to be introduced by Phil Greaves.

[Ed. The illustrations shown here were shot off-screen with a digital camera. With the low light levels involved it was often impossible to avoid long exposures and thus camera shake. I hope, however that they will show enough to be understandable.]

Maurice gave us an entertaining tour through some of things that had interested him, and occupied him, during his career as a scientist.

He started with the problem of bacterial locomotion. The flagellum of a bacterium (prokaryote) is quite different from that of a eukaryote, such as Euglena, where actual waves pass along the flagellum. The main flagellum used can be clearly seen with a good light microscope. It was originally thought that this was a flexible spiral down which waves passed rather like in a rope, with the end firmly attached to the bacterium, thus providing motion. However a series of ingenious experiments showed that a) the flagellum actually revolved, and b) it was a rigid protein structure. The bacterium actually possesses a sophisticated flagellal 'motor', with the flagellum acting like a propeller.

What seems like a single flagellum is shown to be a number of flagella bundled together; the electron micrograph of the bacterium on the left shows the individual flagella unbundled, the diagram on the right shows how the flagella re-arrange themselves to reverse the direction the bacterium swims in.

Maurice showed that life style was no obstacle to developing flagella: below shows that sheathed (left) or sessile (right) bacteria can all develop flagella

Maurice then went on to discuss other directions his career took. He studied the ecology of the rivers Wey and Thames; quite a hot topic in view of environmental concerns. Where chromobacteria were concerned he discovered new species.

The map on the left shows the various stations on The River Wey that Maurice used in his work - a comprehensive study, both temporal and spatial, of the bacteria initially, and then of one of his favourite group - the diatoms.

One of the interesting things about the diatoms is the wide variety of symmetries they show: 2,3,4 and 5!

He is also an active member of the British Mycological Society, and in an earlier talk some years ago I recall he discussed some of the toxins that affected tobacco and grains. Here he showed two interesting slides; one of a beautiful growth on an agar plate, and evidence that at least one country understands the importance of mycology - and microscopes!

He barely had time to mention his great interest (and knowledge of) butterflies and moths!

The end of his talk was greeted with warm applause. I had to leave before questions, but it was clear that everybody had thoroughly enoyed this tour of his career and interests.

Tony Saunders-Davies